Transmission of power by belt can be accomplished by a driver pulley and a single or series of driven pulleys about which a belt is trained. It is occasionally necessary for the belt to change direction as it operates between the driver and the driven in order to clear other components. In this case, the belt can be trained over idlers which allow the belt direction to be changed with minimal loss of efficiency. Further, for tensioning the belt, automatic tensioners can be used. In such case, the idler pulley is installed on the tensioner pivot arm.
Idlers generally comprise a base that is mounted on a non-rotating surface. The belt bearing surface or pulley is then rotatably connected to the base by means of a bearing. The bearing may be a ball bearing type having an inner and outer race. In most arrangements, the inner race of the ball bearing is attached to the idler base or to the non-rotating mounting surface directly. The idler pulley is then attached to the outer race of the ball bearing. The outer race and the pulley rotate together.
Representative of the art is U.S. Pat. No. 5,725,448 to Kato et al. which discloses such a pulley body fitted to an outer race of a ball bearing.
It is also possible to attach the pulley to the inner race of the ball bearing, with the outer race being fixedly attached to a mounting surface.
Representative of the art is U.S. Pat. No. 5,421,788 to Toth which discloses a belt tensioner having an idler pulley and bearing assembly. The idler pulley and bearing assembly comprise a non-rotating outer race and a pulley shaft extending through an inner race. The pulley is fitted to the inner race by means of the shaft, which shaft is pressed together with a retaining cup to hold the pulley shaft within the bearing inner race.
The prior art teaches a pulley shaft which is used to mount a pulley to a bearing race. This increases the cost of the idler with respect to the material cost as well as for machining and assembly.
What is needed is an idler pulley having a web mounted to an inner race of a bearing. What is needed is an idler pulley having a web affixed to an outer surface of an inner race of a bearing with a fastener. What is needed is an idler pulley having a web mounted to an inner race of a bearing with a lip for alignment. The present invention meets these needs.